FOXBORO -- The first training camp practice of the year was held out on the practice fields behind Gillette Stadium one day after all conditioning tests were completed. Bill Belichick said before the session that everyone who was under contract was present and accounted for. Whether or not they practiced was another story. Details below on everything from the attendance to the practice schedule to the standout plays.

WEATHERDay 1 was spent under some significant cloud cover, but there was nothing more than a few intermittent raindrops that came down in the last hour of practice. Temperatures hovered in the low-70s, making it a pretty comfortable day.

WHAT THEY WOREHelmets and shorts were the order of the day, making the session look like little more than an extension of OTAs and minicamp. The lone difference? Numbers on the jerseys.

WHO WASN'T THERERookies Chris Martin and Deontae Skinner were not present. Rookie receiver Jeremy Gallon wasn't around for the start of the session, but he was out on the field a few minutes into practice. Tommy Kelly, Aaron Dobson, Alfonzo Dennard, Matthew Slater, Dominique Easley and Gallon were not in uniform and worked out as part of a separate group.

NEWS OF NOTERob Gronkowski was on the field for his first practice with the team since tearing his ACL and MCL last season. Wearing a brace on his right knee -- as well as a brace on his left arm -- he was limited in his participation, not taking part in any 7-on-7 or 11-on-11 work. But when he was involved, he moved well in and out of his breaks and made a handful of leaping catches in the end zone. It may be a while before Gronkowski is at full strength, but he did not look all that slowed going against air on Thursday.

WHAT THEY DIDThe team warmed up with half speed plays, which then took them into their stretching period. Wideouts and quarterbacks warmed up with some agility work.

While punter Ryan Allen worked by himself on his footwork, running backs took their turns working on ball security and high-knee drills. Defensive players did a series of agility drills before the practice got started in earnest.

Defensive backs worked on their coverage in the end zone while quarterbacks and receivers worked on making their connections with no defense in the red zone.

After some ball-protection drills and special teams work, the offense and defense had a chance to get after each other a little bit with 7-on-7 and 11-on-11 work.

The practice finished up with some two-minute hurry-up repetitions.

WHO'S HOT* Gronkowski for the sheer fact that he looked to be unencumbered by his knee.

* Kenbrell Thompkins had a very good day. Not only was he invited to work with Tom Brady, Gronkowski, Julian Edelman and Danny Amendola in a side session where those five worked on their goal-line routes, he also made a handful of impressive catches. His best of the day came from Jimmy Garoppolo when Thompkins laid out, fully-extended and landed in the zone for a touchdown.

* Brandon Browner got a rise out of the bleachers packed with fans when he broke up a pass from Brady that was intended for Edelman. In a practice that was mostly lacking in physicality, it was an aggressive, physical play from a defender known for those characteristics. He probably can't wait for the pads to be introduced on Saturday.

WHO'S NOT* Ryan Mallett didn't light the world on fire. Hard to tell if it's his mistake or the receiver's when there's a miscommunication, but it happened more than once on Thursday. Overthrows also seemed to be an issue for him.

* Brandon Bolden was the only player to lose his grasp on a ball in ball-protection drills. It happens, but not exactly the way you're looking to start camp -- especially when you may be on the cusp of making the team because of a crowd at that position.

WHAT WE SAW* Early on in tight end drills, Gronkowski stutter-stepped around a bag, planted on his right leg, and went to corner of the end zone for a touchdown catch. He was moving very well considering the circumstances.

* The rehab group appeared to be doing some fairly strenuous work. To see Dobson and Slater running with resistance bands and alternating hopping up and down on one leg appeared to be a good sign that those players were coming along.

* Belichick stepped in at center while defensive linemen worked on a drill that seemed focused on defending the run. Joe Vellano put him on skates and drove Belichick into the backfield, which got a quick smile from the coach as he made his way back to the line.

* Josh Boyce was active in kick-return duty while Shane Vereen was with him as the director of traffic -- Slater's job in the regular season, normally. Roy Finch and James White also took reps in the kick-return game.

* During special teams work, Brady pulled aside what seem to be his favorite targets -- Gronkowski, Thompkins, Edelman and Amendola -- to work on goal-line routes. We saw him do this kind of thing with Julian Edelman and Danny Amendola in OTAs and minicamp, but Thompkins was not invited. His inclusion -- and Brady's praise of the second-year wideout after practice -- bodes well for his role going forward.

* In that separate side session -- which seemed to be run by Brady but was overseen by tight ends coach Brian Daboll -- Brady was very particular about which way he wanted routes run and spent a few minutes after the brief session explaining the intricacies of that which he was looking for.

* After the entire offense worked on its goal-line package, the Patriots ran an interesting drill in which the quarterback took a push in the back, set his feet and threw about 10 yards to a back or a tight end who turned up-field and had to make a one-on-one move. That was followed by smoke and bubble screens at the goal line.

* Usually it's Stevan Ridley who has the most vibrant footwear in any given Patriots practice but today it was Thompkins (neon orange spikes) and Darrelle Revis (neon yellow).

* Patriots jerseys featured a new font for their numbers. They looked a little longer and cleaner -- very easy to read from afar.

* Brady finished the day on the practice fields by running through the passing tree with Gronkowski. He then went to the back corner of one field to do some final conditioning work with Mallett and Garoppolo.

* Defensive tackle Sealver Siliga got plenty of reps early in the final 11-on-11 period. Chris Jones appeared to be the first man in for the defensive line on a substitution during that session.

WHAT THEY SAID"I’m looking forward to that opportunity and the big challenges that are ahead. It’s good to be out on the field; good to get going." -- Bill Belichick before taking the field for Day 1 of camp.

Phil Perry serves as a general reporter for Comcast SportsNet, mainly covering the New England Patriots. Follow Phil on Twitter here.